AA, Combined Paper on Sustainable Cooling Strategy UEA,,Jan 2008


Published on

  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

AA, Combined Paper on Sustainable Cooling Strategy UEA,,Jan 2008

  1. 1. Re-conceiving the Built Environments of the Gulf Region Precedents Courtyard Tradition in Islamic Architecture Challenging the Supremacy The courtyard form has a long tradition in Islamic architecture. Study of some of the palace complexes sunshine. The graph, Fig. 4c, shows outdoor, courtyard and indoor temperatures measured over four consecutive surviving in Spain has provided insights on how the days. With the outdoor air reaching peaks of 31-35C of Airconditioning courtyard and the shaded porticos that surrounded them helped modulate indoor environmental conditions under the very intense summer conditions experienced in the those in the courtyard are lower at 27-30C and are further reduced indoors by the thermal inertia of the building. The daily range of 18-25C and average of 22C achieved Simos Yannas south of the country. Measurements taken recently in the indoors is quite remarkable and is achieved despite the Director, Environment & Energy Studies Programme, Architectural Association School of Architecture, London 14th century Palace of the Lions, Fig. 4 a-b, a residential fact that the courtyard is now operating without the lavish complex of the Alhambra in Granada show the role of the vegetation that used to populate it and which has been courtyard and its porticos as transitional spaces mitigating recently removed to protect the building’s foundations Introduction the effects of the outdoor temperature and intense summer from moisture (Jiménez Alcalá 2002). The absolute dependence on mechanical air conditioning as now commonly understood by the international that characterises contemporary buildings in the UAE is a scientific and engineering communities; second, a better major issue that is both poorly understood and potentially understanding of the technical aspects of building design intractable. While the more extreme periods of high for these climates; third, an equally improved approach to ambient air temperatures and humidity that characterise the microclimatic design of outdoor spaces. the climates of the region may be alleviated by the use of In view of the absence of any environmentally air conditioning, there is no technical justification for the appropriate, contemporary built precedents, a major whole year to be treated the same way other than the climatic research effort will be required to underpin the formulation inadequacy of buildings now being built here. Nor is there of guidelines and regulations to help redirect building any scientific or physiological evidence for the common design and the retrofitting of existing buildings toward practice of maintaining constant indoor temperatures at climatically adaptive and environmentally sustainable the kind of levels commonly provided in winter to heated models. Given that it has taken over thirty years of funded buildings in cold climates. On the contrary, there is widely scientific research and applications in Europe and North accepted empirical research and physiological justification America to make a significant, though as yet far from for abandoning such practice so that both residents and sufficient or satisfactory, difference in the environmental visitors can respond to daily and seasonal variations of the performance of buildings, the effort required will be outdoor climate through natural adaptive processes of the substantial. However, the likely cost of any such research human body. Currently, the temperature difference between is insignificant compared to the saving in capital and the airconditioned spaces inside buildings and the streets running costs it can help achieve. Challenging as the and urban spaces outside frequently rises above 20 degrees technical research might be in order to bridge the present centigrade, high enough for a thermal shock when entering knowledge gap as quickly as possible, it cannot even start Fig. 4a Fig. 4b or exiting airconditioned buildings and motor cars. Heat without a change in the cultural perception of the role of discharges from airconditioning equipment, and from the mechanical AC. The current dependence on mechanical power stations that produce the electricity used to drive AC must be challenged, its operational characteristics building appliances, lead to urban warming. In Dubai this ought to be rethought and the environmental attributes and is bound to keep increasing at a fast rate owing to the intense expectations from the buildings being built in the Region building activity leading to additional heat discharges from should be reconceived. airconditioning plant. One effect of urban warming is to Our Masters Programme in Sustainable Environmental drive cooling loads for buildings higher, calling for larger Design at the Architectural Association School of airconditioning plant and/or more energy to operate it. Architecture in London is committed to exploring Another is the deterioration of environmental conditions architectural solutions that can achieve thermal and outdoors, undermining the usability of outdoor spaces, a visual comfort at near zero carbon emission for most serious blow to the essence of any city. At the rate at which new buildings in most climatic regions. In response to building activity is now taking place in the UAE, a complete Nader Ardalan’s call for an environmental agenda for abandonment of the outdoor environment for a network of the Gulf Region we undertook a series of studies that enclosed, airconditioned malls is probably only a matter of combined reviews of historic precedents with parametric time. Were this to happen it could mean the return of the studies using computer simulation models and fieldwork outdoor urban environment to a far worse desert than the involving short-term measurements in the warmest period one from which it was won. This could severely erode the of the year. These are summarized in the next section of value of property and businesses housed here. To prevent this article. The studies led to the formulation of some Fig. 4c such fate and contribute to the use and enjoyment of the preliminary guidelines that were tested on a variety of city it is essential to narrow the temperature differences building programmes. The projects developed for these between indoor and outdoor spaces. This will require, first, programmes are illustrated in the final section of the Fig. 4 The Palace of the Lions, Alhambra, Granada, Spain. (a) View of the courtyard (b) Section showing solar control provided by the porticos at midday on solstices and equinox (c) Temperature measurements over a four-day period in summer the acceptance of adaptive standards of thermal comfort article. showing modulating effects of courtyard, porticos and the building’s thermal inertia.42 Architecture & Art Architecture & Art 43
  2. 2. The courtyard with a height to width ratio of 1.8:1, is exposed to the sun for part of the day. The difference Courtyard House and Transitional Structures Fig. 5b, recorded the lowest temperature by 1-3K from reaches some 1.5K during the peak midday sunshine in old Dubai the street of 2:1 height to width ratio, Fig. 5c, and by as period falling to nil at the end of the day as both spaces cool much as 4-6K from the YHA readings. However, on the toward the ambient air temperature after sunset. Exposure day of the measurements this advantage was counteracted to the sun in the open street leads to surface temperature A series of short-term measurements of temperature and found sitting there. The results show considerable but by higher measured relative humidity in the area of the that are higher than the air temperature thus having a relative humidity were undertaken in outdoor and semi- systematic differences between the “dry” inland reference Bastakia owing to Northerly winds blowing from the negative effect on pedestrian comfort. On the day of the outdoor spaces in areas of Dubai during July 2007 in the location and the wetter locations of the old town and the creek. measurements the mean radiant temperature in the open hottest period of the year (Thapar 2007). The measurements waterside new developments. These provide some useful In Deira, a densely built shopping district developed street was estimated to be higher by over 5K at 2pm. On were taken in Bastakia and Deira and in outdoor locations insights on improving microclimatic conditions in this in the 1960’s, the measurements were taken in the Gold the other hand, being protected from the sun throughout near the water and the city’s new developments. These city. Souk, in a street parallel to the souk, and near the water the day, the building surfaces surrounding the souk would were then compared with readings taken on the roof of Dating from the 1890’s the Bastakia quarters in Dubai along the creek. The graph, Fig. 6a, shows that although remain close to air temperature. The importance of this a three-storey building of the Youth Hostel Association comprise some sixty buildings that form a dense urban not protected from the sun the area near the water was confirmed by the comfort survey which voted the souk (YHA) that was selected as representing a reference urban tissue around narrow winding streets. Measurements Fig. 6b registered the lowest and most stable temperatures area as comfortable whereas the open street was found to temperature unaffected by built form, vegetation or water. were taken in the courtyard of a restored house and in during the hottest part of the day presumably owing to be uncomfortable. This (10 July 2007) was a hot day with At each location measurements were supplemented with nearby streets and compared with readings from the YHA, the stabilizing influence of the water mass and the effect a peak temperature that rose above 45C at the YHA. This a thermal comfort survey among passers-by or subjects Fig.5ad. of evaporation. The Gold Souk, Fig. 6c, which is well makes the reduction of 7-10K achieved by the fieldwork protected from the sun, achieves a lower temperature spots in Deira particularly notable. than the parallel street, Fig. 6d, which though narrow Fig. 5a Fig. 6a Fig. 5b Fig. 5c Fig. 5d Fig. 6b Fig. 6c Fig. 6d Fig. 6 Measurements in Deira Fig. 5 Measurements in Bastakia (a) Graph comparing temperature measurements taken in Gold souk, adjoining street and near the water, (b) water’s edge (c) Gold souk (d) street parallel to souk. (a) Graph comparing temperature measurements taken in courtyard, adjoining street and reference urban location; (b) courtyard ; (c) street; (d) location of reference temperature datalogger on roof of YHA building. The dense organic forms and shaded transitional spaces However, a densely built form can also prevent air flow of Deira and the Bastakia provide some clear microclimatic and reduce air velocity which can be problematic at times. benefits that derive from the resulting solar protection Near the sea the courtyard form needs to be more adaptable and thermal inertia. Jointly these attributes lead to both so as to open to cool breezes, but protect from warmer air lower and more stable temperatures than those resulting at times. in less dense areas with higher exposure to solar radiation.44 Architecture & Art Architecture & Art 45
  3. 3. Dubai Marina and Greens Today Thermal comfort criteria as defined by the international Parametric Studies standard ISO 7730 and the ASHRAE Standard 55-92 can Readings taken in the area of the Dubai Marina and Climate Analysis for Sustainable be satisfied at air and mean radiant temperatures in the the Greens residential area were lower than the YHA Environmental Design range of 19-30oC (Yannas 2007). Temperatures above reference temperatures by up to 7K around midday, 30oC are also commonly tolerated in hot climates Weather data for Abu Dhabi City (24.28oN 54.25oE) Fig. 7 a-c. These effects diminish after sunset. The Marina when air movement is available. Air velocities of up to and Dubai (25.14oN 55.17oE) were obtained using the area is influenced by the proximity of the water and the 1.0m/s are generally acceptable indoors whereas outdoors Meteonorm global meteorological database (Meteotest winds blowing from the Gulf, while Greens displays the in the city air velocities of up to 2.0m/s will help extend 2004). The data files representing ten-year average data effect of vegetation and shading trees. However, again the comfort range further provided subjects are protected for the two cities are almost identical. A summary of mean humidity levels near the sea were significantly higher. from direct solar radiation. Such wider range is consistent daily values of the main parameters is given in Table 1. This is significant as the comfort survey identified high with fieldwork undertaken to assess adaptive practices in The monthly variations of the outdoor dry-bulb humidity as a major discomfort factor that undermined the hot climates (Auliciems and Szokolay 1997; Humphreys, temperature show that the annual cycle can be divided effect of lower air temperatures. Nicol and Raja 2007) and a comfort survey undertaken into three distinct periods, Figs 1-2: a four-month period of last summer (Thapar 2007). With these considerations mild weather (December to March inclusive) characterized thermal comfort can be achieved by natural means in this by daily mean temperatures of 20-23oC; a warm period climate for much of the year. (November and April) with mean temperatures of 25- Sunshine is strong throughout the year with an annual 26oC, and a hot period (May-October inclusive) with mean average of 8 hours of bright sunshine per day, rising to temperatures of 29-34oC. some 10 hours per day in the hot period. Clearly, solar The diurnal temperature range of 10-12K involves protection of occupied spaces is essential outdoors as night-time ambient air temperatures that are low enough for well as indoors throughout the year. The incident solar convective cooling of building structures for most of the radiation is high all year varying in the range of 3.7- year. However, the useful cooling potential available from 7.0 kWh/m2 on unobstructed horizontal surfaces. Roofs, this source is being eroded by the urban warming caused streets, pavements and other exposed manmade surfaces resulting from the heat discharges from airconditioning will get extremely hot affecting outdoor comfort as well as appliances on buildings and motor cars. building cooling loads unless specially treated. Winds average 4.0-4.5 m/s throughout the year the For solar energy applications the prospects are strongest coming from the direction of the Gulf on most extremely good for all types of applications both thermal months except for the hottest months (July-SeptemberFig. 7a Fig. 7b and electric; sun-tracking appliances can intercept as much inclusive) when the predominant direction is recorded as as 6.5-8.5 kWh per m2 collector area daily throughout the South. year. TABLE 1. Monthly Weather Data for Abu Dhabi City Source: Meteonorm Nomenclature Tair Mean daily air temperature (dry-bulb), oC Ta min Mean daily minimum temperature, oC Ta max Mean daily maximum temperature, oC Twet Mean daily wet-bulb temperature, oC GGhor Global (direct & diffuse) solar radiation on the horizontal, kWh/m² mean daily total GDhor Direct radiation on the horizontal,kWh/m² mean daily total Wind Wind speed, m/s WD Predominant wind direction (North=0) Fig. 7c Fig. 7 Measurements in Dubai Marina and Greens (a) Marina (b) Green (c) Graph comparing temperature measurements taken in Dubai Marina and Greens with reference urban location. Overall the comfort survey confirmed people’s high adaptive potential with temperatures close to 40C reported as comfortable by subjects in the shade and exposed to air flow. Wind velocities of 2.0m/s were reported as desirable at these temperatures. As in all hot climates urban activity in Dubai avoids the hottest part of the day. Markets in Deira open at 6am and are deserted at midday. Evenings are the most popular time to enjoy outdoor activity. Fig. 1 Hourly values of direct and diffuse solar radiation on the horizontal and hourly mean, maximum and minimum values of dry-bulb temperature for each month plotted against the calculated adaptive comfort range. Background colour identifies mild, warm and hot periods of the year. (Source: Weather data generated with Meteonorm plotted with Square One Weather Tool). 46 Architecture & Art Architecture & Art 47
  4. 4. Urban Form A number of courtyard variants based on the forms Staggering of blocks leads to improved air flow encountered in old Dubai were modelled using the ENVI- Removing parts of the lower two floors of the courtyard met three-dimensional microclimate model for simulating blocks improves wind penetration inside the fabric as well microclimatic interactions in an urban environment. as creating covered double height urban spaces at road Coutyard height-to-width ratios H/W of between 1.5:1 and intersections; these provide transitional spaces that have 2:1 were considered as providing reasonable shading as better wind access as well as being shaded. well as potential for holding cooler air during daytime,Figs 8 and 9. The simulation studies investigated the effect of openings in the courtyard blocks to improve ventilation conditions. Openings perpendicular to the main streets helped increase air flow. Moreover: Fig.3 Hourly dry-bulb, wet-bulb and sky temperatures at the beginning of the hot period Broader N-S streets (i.e in the direction of the Fig. 2 Sunpath diagram for 24N with mild, warm and hot periods of the year marked. Effective shading is required on all orientations all-year round. (May) and surface temperature on horizontal plane exposed to sun in Abu Dhabi. predominant wind) and narrower E-W streets provide deeper penetration of wind as well as reduced incident solar radiation Wind speeds are highest where the wind enters the urban blocks; these areas are good for public functions that require good airflow. Chamfering of the edges of blocks helps improve ventilation and wind speeds especially in streets perpendicular to the main wind direction. Relative humidity mean daily values of 50-65% Figure 3 shows the hourly patterns of the dry-bulb, wet- conceal fairly high levels of absolute humidity that rise bulb and sky temperatures on a typical day at the beginning to 15-25 g/kg during the hot period. However, with the of the hot period in May. The sky temperature depression exception of three months when the wet-bulb temperature (dry-bulb minus sky temperature) is of 10-13K. This gives is too high, the temperature difference between dry-bulb a measure of the cooling potential by longwave radiation to and wet-bulb (wet-bulb depression) reaches regular peaks the sky. Although this appears to be as high during daytime of 10-15K during daytime indicating useful potential for as at night, during the day the outgoing longwave radiation evaporative cooling if needed. is overtaken by the incoming longwave and shortwave Calculated hourly sky temperature depressions radiation from the sun and sky. At night-time, however, which provide a measure of radiative cooling to the night the net outgoing longwave radiation is sufficiently high to sky are in the range of 10-12K in the hot period indicating lower temperatures of surfaces exposed to the sky below a useful potential at night time. that of the ambient air temperature. This is shown on the The sky luminance is high throughout the year in the graph by a reference surface temperature (yellow line) range 15,000-70,000 lx during work hours in the mild calculated for a horizontal surface with a solar reflectance Fig. 8 Simulation results showing effect on wind velocity of variations in the orientation and period to 50,000-100,000 lx in the hot period about half typical of urban surfaces and with unobstructed view of geometry of courtyard openings. is diffuse illuminance from the sky vault. Under these the Sun and sky. In this case this can be seen to be of conditions 1-2% of the outdoor illuminance is sufficient to the order of 2K relative to the air temperature. During meet required illumination levels for any indoor activities. daytime exposure to solar radiation raises the temperature These fractions can be achieved in buildings with very of such surface well above that of the ambient air making it modest areas of glazing. Highly glazed facades risk serious contribute to the urban heat island effect. The temperature problems of glare as well as excessive cooling loads and elevation would be much higher on darker surfaces such overheating. as asphalt. The graph also indicates the potential for direct evaporative cooling which with a wet-bulb depression varying in the range of 5-15K is quite substantial during daytime at this time. This is progressively reduced in the summer becoming unavailable in the form of direct evaporative cooling toward the middle of the hot period. Fig. 9 Simulation results showing effect on wind velocity and absolute humidity of variations in courtyard openings.48 Architecture & Art Architecture & Art 49
  5. 5. Building Design Hourly cooling loads and indoor resultant temperatures be activated when the outdoor air temperature provided were calculated for a number of building variants using potential for free cooling climatic data for Abu Dhabi and Dubai with the Tas Thermal Transmittances of opaque elements were dynamic thermal simulation model (EDSL 2006). The considered within the range 0.25-1.0 W/m2K for external building specification assumed for these simulation walls and roofs studies was of compact square plan with good access to Cooling setpoints: 22 oC and 29oC daylight. This was tested for both office and residential occupancy with an average rate of internal heat gain of 15 For a base case with a cooling setpoint of 22 oC and Watts per square metre floor area. The following building unprotected windows of a surface area equivalent to 50% parameters were varied as part of parametric studies: of the building’s floor area, the cooling energy requirement was calculated at 230 kWh/m2 building floor area. When Window Areas were varied from a minimum required the main building parameters were optimized this dropped for daylighting to fully glazed elevations. to 96 kWh/m2 for the same cooling setpoint and window Window Orientations: windows were assumed to be to floor ratio, and to 70 kWh/m2 when window areas were equally distributed between two orientations, either North- South or East-West reduced to a lower window-to-floor ratio of 10-25%. Finally, adopting a cooling setpoint of 29oC as suggested Architectural Design Strategies for Sustainability Glazing Type: clear single glazing, clear double by the adaptive comfort algorithms eliminated the need glazing, coated double glazing for airconditioning for a total of at least six months in the Our studies of architectural precedents, field adequate daylighting for the building programme being Solar Control: none, maximum (no direct radiation at year leading to a total cooling energy demand of only 25 measurements, computer modelling and current building considered; owing to high sky illuminance in this climate any time) kWh/m2, an overall saving of some 90 percent compared activity in Dubai and Abu Dhabi have highlighted four this will lead to very modest glazing areas thus reducing Opening area for convective cooling was assumed to the base case, Fig. 10. critical concepts which are central to any consideration cooling loads and the thermal and visual discomfort caused to vary in the range 10-50% of occupied floor and to of sustainable environmental design for the region. These by commonly oversized windows. are: Solar protection is required for all glazed elements on Transition: in the UAE climates all movements between all orientations in this climate; this requires specification indoors and outdoors, and pedestrian activity within and of fixed and/or movable external shading elements on between parts of the city, require solar protection almost elevations. Aiming to control solar gain solely through permanently in conjunction with variable control of air glazing transmittance is insufficient in this climate and flow, air temperature and humidity; these attributes should some of the tinted and reflective glazings that have been be provided by specially designed structures providing used on recent buildings in the region will tend to worsen users the space and time in which to adapt from one thermal and lighting problems. environmental condition to another. Glazing that is protected at all times from direct solar Permeability: this refers to the permanent and/or radiation, and thus receiving solely diffuse radiation from variable extent to which air and moisture should be allowed the sky for daylighting, is not sensitive to orientation as to flow through building envelopes and the urban tissue. the amounts of diffuse radiation do not vary much with orientation. Separation: this refers more generally than the above Provisions should be made for natural ventilation by to the permanent and/or variable environmental coupling controllable means independent of window opening that or decoupling (zoning) of indoor or outdoor spaces could be also operable for night-time convective cooling; the apertures provided for these purposes should not be Identity: materiality, provenance, expression, relevance glazed. (architectural, environmental, sociocultural). In the mild and warm periods of the year between The application of these four concepts is illustrated in November and April, effective solar control in conjunction the projects that follow. The following are specific design with night-time free cooling by natural ventilation is considerations and guidelines derived from this research: sufficient to maintain indoor temperatures within the the adaptive basis of human thermal comfort must be adaptive comfort zone. acknowIedged from the outset; there can be no possible Radiative and evaporative cooling techniques are claim to sustainable environmental design based on complementary and are applicable in the warm and hot conventional airconditioning settings and schedules. periods of the year helping to restore comfort. the creation of transitional structures between spaces Ceiling fans can help extend the upper limits of the at largely different environmental conditions is the most adaptive comfort range in the hot period. fundamental architectural objective in this climate; it is When no combination of the above is sufficient to aimed at protecting from thermal shock as well as reducing provide comfort during occupancy, the spaces to be cooling loads and improving pedestrian thermal comfort. mechanically air conditioned should be zoned so that Heat generating appliances for use in buildings should energy use can be minimised; moreover, the principles be identified by source, magnitude and hours of operation of transition should be respected so as to prevent thermal and their thermal effects decoupled from occupied spaces and visual discomfort when transiting between inside and Fig. 10 Simulated annual cooling energy demand showing effect of applying passive design measures (all runs with a fixed cooling setpoint of 29C; see text for effect of where feasible. outside. different cooling setpoints on cooling energy demand). Glazing should be sized in the first instance to provide50 Architecture & Art Architecture & Art 51
  6. 6. Projects The first set of projects undertaken in 2007 by the In the course of an intensive one-week period the student group on our Masters programme in Sustainable group finalised the design and fabricated the test structure Environmental Design focused on transitional structures. at the AA School’s Hooke Park laboratories in These included canopies, walkways, pavilions, bus shelters Dorset, Fig. 11 a-b. The components of the structure were and sheltered markets. Designs for several such structures then flown to the UAE and the structure was assembled were put forward by the student teams. Dynamic attributes for testing on the campus of the American University that would allow such structures to respond to daily and of Sharjah in February 2007, Fig. 11c. This provided seasonal variations in environmental conditions and to some useful insights on the solar control attributes and occupant requirements were identified. Features singled operability of the structure by its users. However, the out by the project teams in the course of this first stage weather conditions were too mild at the time to test the were then drawn together into a test design that involved structure’s resistance to heat and ability to cool at night. all of the teams working as a single design/build group. Fig. 11 b Building of test structure at AA School’s Hooke Park facility in February 2007 Fig. 11 a Test structure designed by Masters group in January 2007 Fig. 11 c Erecting the structure on the AUS campus, February 2007.52 Architecture & Art Architecture & Art 53
  7. 7. The second set of projects was inspired by Al Lulu The scheme by Surane Gunasekara and Yuan-Chun Lan, Island, an uninhabited, manmade islet off the coast of Abu Fig. 12 a-j, proposes to leave the island as a public resort Dhabi. On a study trip to the UAE in February 2007, our for the city, confining its proposals for new, mixed-use group visited the island and studied the latest proposals development to floating platforms that form bridges with for its development. Back in London a number of projects the city of Abu Dhabi. The scheme’s building proposals were developed by the student teams, some within the illustrate a stepped reduction in built density, starting developer’s masterplan and others as alternatives to that with taller buildings on the city centre side of the bridges masterplan. Some of the resulting schemes are illustrated and tending to low-rise development on the island side here. All of the project teams shared the knowledge of the platforms. Strong environmental considerations acquired from climate analysis, parametric studies using characterise the building design, Fig. 12 g-j, that provides dynamic thermal simulation and the design concepts and clear design applications of the concepts of transition, architectural strategies developed from these studies and permeability, separation and identity, introduced above. summarised in previous sections of this article. Fig. 12c Axonometric views of scheme Fig. 12d Axonometric views of scheme Fig. 12a Proposal to leave Lulu island as a public resource for the city offering a variety of recreational activities. Fig. 12e Axonometric views showing green areas and built zones and land uses of proposed development Fig. 12b Proposed mixed-use development on floating platforms between Abu Dhabi city centre and Lulu. Fig. 12f Axonometric views showing green areas and built zones and land uses of proposed development54 Architecture & Art Architecture & Art 55
  8. 8. Fig. 12g across dwelling unit showing openable components in open and closed positions. Fig. 12j Different degrees of permeability and separation provided by the buildings’ external skin in response to daily and seasonal cycles (left, southern elevation; right northern elevation). The proposal for an arena on Lulu Island by Krista Raines, Fig. 13 a-c, follows from her masterplan with Annisa Julison to develop the island as an Olympic Sports Complex. Multilayered solar protection and good air flow potential were the key considerations for the design and were based on mapping of the daily and seasonal schedules of the sporting activities. Fig. 12h Axonometric view of Southern elevation showing double-layered screen in position providing shading via horizontal overhangs and vertical elements, and air flow through permeable second screen layer. Fig. 13a Proposal to develop Lulu Island as a sports complex. Fig. 12i View from inside.56 Architecture & Art Architecture & Art 57
  9. 9. Fig. 13b Fig. 14c Air flow simulation showing effect of different wind speeds and roof canopies Fig. 13b - c Axonometric views of proposed arena. Fig. 14d Day and night views of stadium showing roof shading and cooling devices The multipurpose stadium proposal by Natalia Kokosalaki, Fig. 14 a-f, provides generic solutions applicable in hot climates with spectator areas that are open to air flow, but well protected from the sun and served with natural cooling from retractable passive downdraught evaporative cooling towers (Kokosalaki 2007). Fig. 14e Plan of stadium showing occupancy strategy with openings for airflow through spectator tiers. Fig. 14a Axonometric of stadium identifying the geometry of Fig. 14b Percentage shading achieved by the roof components at different times. roof components optimised for shading the spectator areas Fig. 14f Section.58 Architecture & Art Architecture & Art 59
  10. 10. The scheme by Yasamin Arbabi, is for a high-density, low-rise residential cluster based on a masterplan for the island developed with Harsh Thapar as an alternative to that of the developers, Fig. 15 a-b. The proposals make extensive use of private and public transitional spaces that help ensure solar protection and good airflow through the cluster, as well as radiative cooling techniques for the individual dwelling units Fig. 15 c-h. Figs. 15d - c plan, section and axonometric vies of low-rise residential cluster. Figs. 15 a-b Masterplan proposal for Lulu Island. Fig. 15e - c plan, section and axonometric vies of low-rise residential cluster. Fig. 15f-c Section through dwelling unit showing cross ventilation paths60 Architecture & Art Architecture & Art 61
  11. 11. The scheme by Tiffany Broyles and Anya Thomas proposes the development of second homes along a beach boardwalk that includes provision of transitional spaces for public use, Fig. 17 a-b. The boardwalk structure provides a continuous shaded path with the dwelling units opening from or closing into the structure as required by the owners, Fig. 17 c. The sea side elevation of the units is conceived as an adjustable grid that can provide variable air and light permeability over daily and seasonal cycles controllable by occupants or automatically, Fig. 17 d-e. Fig. 17a Boardwalk along Lulu coast Fig. 17b public spaces along boardwalk The following proposals are for schemes that can easily fit within the developer’s current masterplan. The scheme by Kanika Agarwal and Vidhi Gupta, Fig. 16, is for a holiday resort on the Gulf side of the island. This emphasises the use of semi-open, transitional spaces and experiments with the air permeability of building structures and with proposals for roof cooling techniques. Fig. 16a Site Location Fig. 17c Dwelling units along boardwalk Fig. 17d Fig. 16b Fig. 16c Fig. 16d Figs. 17d-e-f Seaside elevation of unit and detail conceived as a grid of adjustable opening and permeability for daylight and air flow. Figs. 16a-b-c-d Proposal for a holiday resort on the north-west coast of Lulu island.62 Architecture & Art Architecture & Art 63
  12. 12. The office design by Annie Diana Babu, Figs. 18 a-d, provides a compact shaded envelope facing North and South with daylit interior and good airflow potential for passive night-time cooling. References Auliciems, A. and S. Szokolay (1997). Thermal Comfort. PLEA Note 2. Passive and Low Energy Architecture International. ENVI-met (2006). Version 3.0. University of Bochum. EDSL (2006). Tas v9.0.9 Software. Environmental Design Solutions Limited. Fanger, O. (1970/1982). Thermal Comfort. Danish Technical Press. Humphreys, M. A, J.F. Nicol and I.A. Raja (2007). Field Studies of Indoor Thermal Comfort and the Progress of the Adaptive Approach. In Advances in Building Energy Research, Vol.1, pp55-88. Earthscan. Jiménez Alcalá, B. (2002). Environmental Aspects of Hispano-Islamic Architecture. PhD Dissertation Environment & Energy Studies Programme, Architectural Association School of Architecture, London. Kokosalaki, N. (2007). Lightweight Stadium for Hot Climates. MArch Dissertation, Environment & Energy Studies Programme, Architectural Association School of Architecture, London. Meteotest (2004). Meteonorm version 5.1.7 software. Global Meteorological Database for Applied Climatology. Meteotest, Bern. Square One (2006). WeatherTool software. Thapar, H. (2007). Microclimate and Urban Form for Dubai. MSc Dissertation. Environment & Energy Studies Programme, Architectural Association School of Architecture, London. Yannas, S. (2007). Sustainable Environmental Design for the Built Environment. Gulf Research Project Special Report. AA School of Architecture, London. Yannas, S. (2007). Dynamic Structures. Proc. 2nd PALENC Conference, Vol.II pp1146-1151. Yannas, S., E. Erell, J.L. Molina (2006). Roof Cooling Techniques. Earthscan / James & James. Fig. 18a sections showing transitional space on the south side of building and openings for daylighting and fresh air supply at centre of plan Acknowledgments The following Masters students of the 2006-07 my colleagues Werner Gaiser, Klaus Bode, Gustavo academic year collaborated on projects described here: Brunelli and Raul Moura for their contributions to the Kanika Agarwal, Yasamin Arbabi, Annie Diana Babu, year’s teaching. Tiffany Broyles, Matthew Frankel, Surane Gunasekara, Vidhi Gupta, Annisa Julison, Min-Hui Lai, Yuan-Chun MSc / MArch Sustainable Environmental Design, Lan, Farah Naz, Krista Raines, Sachin Rastogi, Harsh Architectural Association School of Architecture Thapar, Anya Thomas, Lydia Yiannoulopoulou. The The main research object of the Master’s Programme measurements at the Palace of the Lions in Alhambra were in Sustainable Environmental Design is the relationship carried out by Benito Jiménez Alcalá as part of fieldwork between architectural form, materiality and environmental for his PhD research completed under my supervision at performance, and how this should evolve in response Fig. 18c the AA School in 2002. The measurements in Dubai and to climate change and newly emerging programmatic microclimatic simulations using the ENVI-met software requirements in urban environments. The taught were performed by Harsh Thapar as part of the research programme is in two stages. In the first stage (October- for his MSc Dissertation Project completed in September April) team projects act as vehicles for exploring the 2007. The stadium proposals by Natalia Kokosalaki form principles and tools of sustainable design introduced in part of her MArch Dissertation Project completed in lectures and software workshops. Project teams combine February 2007. MSc and MArch candidates. In the second stage MSc I would like to thank Prof. George Katodrytis and the and MArch candidates work separately on individual American University of Sharjah for hosting our group and dissertation projects. MSc dissertation projects combine allowing us to assemble and test the structure on the AUS design research with case-study work related to candidates’ campus; Dr Senthil Nathan and the Abu Dhabi Colleges backgrounds. MArch dissertation projects extend into for their hospitality in Abu Dhabi; Robert Hudson of a design application with Phase 1 completed within the Mouchel Parkman for guiding our visit to Lulu Island; current academic year and Phase 2 continuing into the Nader Ardalan for sponsoring the projects described in following Autumn Term. this paper as part of his Gulf Research Project initiative; www.aaschool.ac.uk/ee64 Architecture & Art Figs. 18c-d Southern elevation and views into transitional space Architecture & Art 65